There has been known a sample analysis device utilizing localized surface plasmon resonance (LSPR). Such a sample analysis device includes, for example, nanobodies covered with a metal film. The nanobodies are formed sufficiently smaller than, for example, the wavelength of an excitation light. When the metal film on the nanobody is irradiated with an excitation light, all electric dipoles are aligned, and thus an enhanced electric field is induced. As a result, a near-field light is generated on the surface of the metal film. A so-called hotspot is formed.
In “Localized surface plasmons, surface plasmon polaritons, and their coupling in 2D metallic array for SERS”, written by Lupin Du, et al., OPTICS EXPRESS, USA, issued on Jan. 19, 2010, Vol. 18, No. 3, pp. 1959-1965, nanobodies are arranged in the form of a lattice at a given pitch. When the size of the pitch is set to a size corresponding to the wavelength of the propagating surface plasmon resonance (PSPR), the enhancement of a near-field light is observed on a metal film on a nanoparticle.